There is a tweet from Elon many months prior to the first launch that says "We've decided not to build a deluge system. That may turn out to be a mistake".

They're testing and developing and learning. They're taking risks and making improvements as needed.

As the most successful rocket company of all time by a VERY large margin, I'm pretty sure they know a heck of a lot more about rockets than you and I do, I'm willing to let them make the expert decisions.

It was very shocking to see that they didn't have one. It's not like this was one of those secret things that NASA has done that prevents others from having success. As recently as during SLS ramp up, I remember articles covering the testing of the deluge system for SLS. They talked about how many gallons per second, and the total amount of water necessary, and all of the other blah blah blah details that a non-rocket scientist like me read and was aware of being something necessary. The fact that SpaceX did not have this was quite laughable. Like nobody ever at SpaceX raised a hand in a meeting to bring up this issue, or it was brought up but then slapped down with a "let's don't be silly" type of response? I think the latter would be worse than the former.